How to get keySet() and size() for entire GridGain cluster?

Question

GridCache.keySet(), .primarySize(), and .size() only return information for that node.

How do I get these information but for the whole cluster?

Scanning the entire cluster "works", but all I need is the keys or the count, not the values.

The problem is SQL query works if I want to find based on an indexed field, but I can't find based on the grid cache entry key itself.

My workaround that works but far from elegant and performant is:

Set<String> ruleIds = FluentIterable.from(cache.queries().createSqlFieldsQuery("SELECT property FROM YagoRule").execute().get())
        .<String>transform((it) -> (String) it.iterator().next()).toSet();

This requires the key is the same as one of the field, and the field need to be indexed for performance reasons.

Answer 1

Next release of GridGain (6.2.0) will have globalSize() and globalPrimarySize() methods which will ask the cluster for the sizes.

For now you can use the following code:

// Only grab nodes on which cache "mycache" is started.
GridCompute compute = grid.forCache("mycache").compute();

Collection<Integer> res = compute.broadcast(
    // This code will execute on every caching node.
    new GridCallable<Integer>() {
         @Override public Integer call() {
             return grid.cache("mycache").size();
         }
    }
).get();

int sum = 0;

for (Integer i : res)
    sum += i;